Book/Report

FZJ-2018-03190

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Untersuchungen zum Abbau von Benzoesäure durch ein Gram-negatives Bakterium unter Denitrifikationsbedingungen

Raphael, T. (Corresponding author)FZJ*

1989
Kernforschungsanlage Jülich, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/18695

Report No.: Juel-2322

Abstract: Microbial degradation of aromatic compounds, especially benzoic acid, was investigated in batch and continuous cultures under denitrifying conditions. A bacterium which was able to use benzoic acid as sole source of carbon and energy under denitrifying conditions was isolated during a one year period from sewage sludge. Thestrain was a gram-negative aerobic very short with similarity to the genus M oraxella. It was found that the growth rate of this strain in a denitrifying batch-culture is dependant on the method of preculturing. Inoculation of batch-cultures with bacteria from continuous cultures did not give reproducible growth rates. At present there are no explanations for this phenomenon. In batch-cultures 4 rnmoles of benzoic acid were degraded under reduction of 20 mmoles of nitrate. Nitrite as an intermediate product was detected in concentrations up to 17 mmoles/l. Degradation of $^{14}$C ring-labeled benzoic acid under strict anoxic conditions in batch culture resulted in the following distribution of radioactivity: - 33,5 % as CO$_{2}$, - 34,5 %, in bacterial dry mass and - 31,1 % in the remaining mineral medium.Maximum growth rate in batch culture was estimated at 0,1/h with variable concentrations of nitrite as intermediate. In continuous cultures no nitrite was detectableunder nitrate-limitation but nitrite accumulated inhibition of groth could be observed under limitation of benzoic acid as carbon and energy source. Maximum growth rate in nitrate-limited continuous culture was 0,17/h and 0,08/h in benzoic acid limited culture. The saturation constant for nitrate was determined as 5 $\mu$mol and for benzoic acid 0,15 mmol. Under different conditions of culture instability a likely intermediate of benzoic acid degradation could be detected. The structure based on GC/MS studies was proposed as 2,4 heptadienedicarboxylicacid. This compound was also found in aerobic cultures. A biotechnical utilization of anoxic degradation of aromatic substances could be useful with this or other strains because of the relatively fast growth rates achieved.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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Database coverage:

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